1. Field of the Invention
The present invention relates to a fluorescent lamp driver for driving a fluorescent lamp to emit light and to a liquid crystal display apparatus.
2. Description of Related Art
For example, in a display apparatus that is not of a self-luminous type such as a liquid crystal display, a backlight using a cold cathode fluorescent lamp (CCFL) as a light source is provided. FIG. 7 schematically illustrates a constitution of a fluorescent lamp driver of a related art for driving the cold cathode fluorescent lamp as a backlight provided in such a liquid crystal display apparatus. In FIG. 7, a drive/control circuit 50 is provided with a switching element or the like therein so as to receive power supply from a DC power source not shown in the figure to generate an AC voltage. This AC voltage generated by this drive/control circuit 50 is supplied to primary winding N1 of a transformer TR.
The transformer TR is a step-up or step-down transformer and excites an AC voltage received from the drive/control circuit 50 to output to secondary winding N2. One end of the secondary winding N2 of the transformer TR is connected to one terminal t10a of a cold cathode fluorescent lamp 10, while the other end of the second winding N2 is connected to the other terminal t10b of the cold cathode fluorescent lamp 10, and at the same time, connecting points of them are grounded.
In the example of the related art, there has been employed a constitution in which the terminal t10b of the cold cathode fluorescent lamp 10 is set to an earth potential or a potential close thereto while an AC voltage is applied to the terminal t10a. Namely, in the fluorescent lamp driver in this case, as shown in FIG. 8, for example, by applying a voltage V having±V level taking 0 level as a reference to the terminal t10a of the cold cathode fluorescent lamp 10, the cold cathode fluorescent lamp 10 is driven to emit light.
As the related art, the following patent document can be cited.    [Patent Document 1] Japanese Patent Application Publication (KOKAI) No. 11-8087